Dissertation > Environmental science, safety science > The basic theory for the Environment and Science > Environmental Biology > Environmental Microbiology

Microbial Degradation of Tribenuron-methyl

Author WangZuoXi
Tutor LiuShuangJiang
School University of Science and Technology of China
Course Biochemistry and Molecular Biology
Keywords Sulfonylurea Tribenuron-methyl (TBM) biodegradation acidohydrolysis Serratia Bacillus 2-Methoxy-4-methyl-6-(methylamino)-1,3,5-triazine demethylation 16S rRNA genelibrary
CLC X172
Type PhD thesis
Year 2013
Downloads 65
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Sulfonylurea herbicides were wildley used in weed control, as the world’s largest class of herbicides, which possess high activity, stability, specificity and low toxicity. Tribenuron-methyl (TBM), as a member of the herbicides, was in large scale use in the major wheat-growing areas in China,such as Shandong, Henan and so on, which caused some influence on China’s grain production and ecological environment.TBM degrading bacteria were enriched with TBM as potencial carbon, nitrogen or sulfur source, and70bacterial iolates were obtainted, whose degradation of TBM and factors were also evaluated. Serratia sp. strain BW30was selected and subjected to intensive investigation on its degradation mechanism. TBM degradation by strain BW30was dependent on glucose or other fermentative carbon sources with short-chain fatty scids (lactic or oxalic acid) and the products were methyl2-(aminosulfonyl)benzoate and2-methoxy-4-methyl-6-(methylamino)-1,3,5-triazine. In addition, indigenous earthworms and Bacillus sp. BS2were applied to augment TBM degradation in lab-scale soil column experiments, whose results demomstated Bacillus strain BS2and earthworms significantly increase TBM removal,respectively.A mixed flora that degraded2-methoxy-4-methyl-6-(methylamino)-1,3,5-triazine in12d was obtained from the enrichment of mix soil sample from Henan, Hebei, Shandong and the Northeastern, Although several medium and isolation method had been essayed, no positive result appeared. One of degradation products was idenfited, that methyl was removed from the2-of triazine ring, which was not the end product of the degradation pathway. And then, we constructed16S rRNA libraries on the mixed flora, analyzing its compositin and making a contradistinction to the isolated strains from the flora, which provides a material reserve for the next research.

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